1. Field of the Invention
Embodiments of the present invention relate to the fabrication of integrated circuits. More particularly, embodiments of the present invention relate to a process for depositing and post-treating low dielectric constant films.
2. Description of the Related Art
Semiconductor device geometries have dramatically decreased in size since such devices were first introduced several decades ago. Since then, integrated circuits have generally followed the two year/half-size rule (often called Moore's Law), which means that the number of devices that will fit on a chip doubles every two years. Today's fabrication plants are routinely producing devices having 0.13 μm and even 0.1 μm feature sizes, and tomorrow's plants soon will be producing devices having even smaller geometries.
In order to further reduce the size of devices on integrated circuits, it has become necessary to use conductive materials having low resistivity and to use insulators having low dielectric constants (k) to reduce the capacitive coupling between adjacent metal lines. Recent developments in low dielectric constant insulating films have focused on incorporating silicon (Si), carbon (C), and oxygen (O) atoms into the films. One challenge in this area has been to develop a Si, C, and O containing film that has a low k value and also exhibits desirable thermal and mechanical properties. Often Si, C, and O containing films that have a desirable dielectric constant exhibit poor mechanical strength and are easily damaged by etch chemistry and plasma exposure during subsequent processing, causing failure of the integrated circuit.
Thermal and plasma annealing processes have been developed in attempts to improve the properties of low dielectric constant films. Thermal and plasma annealing processes have typically been performed at temperatures of less than about 400° C. in order to prevent damage to other components of the substrate or device on which the low dielectric constant film is deposited. It has been found that thermal and plasma annealing processes can densify low dielectric constant films containing Si, C, and O. However, such annealing processes typically are performed for about 30 minutes to 2 hours, and thus significantly increase substrate processing times. Also, further improvements in the mechanical and dielectric properties of the low dielectric constant films are still desired.
Thus, there remains a need for a method of post-treating low dielectric constant films to improve the properties of the low dielectric constant films.